Re: [Discuss-gnuradio] Simple digital data transmitter

[marcin_w]

Eric Blossom wrote:
> 
> Your baseband sample rate is 100M/32 -> 3.125MS/s
> 
> You're using 2 samples/symbol, thus your symbol rate is 
>   3.125MS/s / 2 -> 1.5625Msymbols/s
> And since you're using DBPSK, you're getting 1 bit/symbol, thus your
> raw over-the-air bit rate is 1.5625Mbit/s
> 

Hi Eric, a quick question about this.

According to:
 _pick_bitrate(bitrate, bits_per_symbol, samples_per_symbol, xrate,
converter_rate, xrates, gen_info) in pick_bitrate.py

when the samples per symbol and interpolation are given, then our bitrate
can be determined straight away.
i.e Bitrate = converter_rate / xrate / samples_per_symbol

Is this correct though, in determining the bitrate for both dbpsk & dqpsk?
For instance if we passed the_pick_bitrate() function an interpolation of
128 and Samples/symbol of 2, then according to the code, our bit rate for
both dqpsk and dbpsk will be 500kbs.

But according to what your saying:
1) for dbpsk

if DAC rate = 128e6  Interpolation = 128  Samples/symbol = 2
Bitrate = 128e6 / 128 / 2 = 500k

2) for dqpsk

Using the same parameters
Bitrate = 128e6 / 128 / 2 / 2bits per symbol = 256K

Have i missed something here, or in the code?

Regards,

Marcin









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